Abstract
This study addresses the achievable sum-rate for the uplink of a cloud radio access network (C-RAN) operating in a linear Wyner-type topology, i.e., with partial channel connectivity. In the system, the radio units (RUs) communicate with a central, or cloud, unit (CU) by means of digital finite-capacity fronthaul links. The messages sent by the user equipments (UEs) are jointly decoded by the CU based on the compressed baseband signals received on the fronthaul links. Unlike prior works, each RU is assumed to be also connected to its neighboring RUs via finite-capacity fronthaul links. Under the standard assumption that the RUs do not perform channel decoding (i.e., oblivious RUs), each RU performs in-network processing of the uplink received signal and of the compressed baseband signal received from the adjacent RU, with the CU carrying out channel decoding. A closed-form expression of the achievable sum-rate is derived assuming point-to-point compression, and then analytical expressions are provided for more advanced fronthaul compression schemes that leverage side information. Numerical examples provide insights into the advantages of inter-RU communications and into the performance gap to existing sum-rate upper bounds.
Highlights
Cloud radio access network (C-RAN) is an established architecture for 5G systems, in which the baseband signal processing functionalities, which are currently performed at the base stations (BSs) in LTE deployments, are migrated to a baseband processing unit (BBU) pool located within a cloud unit (CU) [1]
We examine the potential advantages of inter-radio units (RUs) cooperation as enabled by inter-RU fronthaul links in terms of achievable uplink sum-rate performance
Under the standard assumption that the RUs do not perform channel decoding, i.e., oblivious RUs, each RU performs in-network processing of the uplink received signal and of the compressed baseband signal received from the adjacent RU, with the CU carrying out channel decoding
Summary
Cloud radio access network (C-RAN) is an established architecture for 5G systems, in which the baseband signal processing functionalities, which are currently performed at the base stations (BSs) in LTE deployments, are migrated to a baseband processing unit (BBU) pool located within a cloud unit (CU) [1]. In [2]-[7], distributed compression techniques were studied, whereby the CU leverages the statistical correlation of the received signals across nearby RUs. The works [3] and [5] investigated methods based on successive decompression and channel decoding, while the papers [2], [4] and [7] analyzed the performance gains that are achieved via joint decompression and decoding. We examine the potential advantages of inter-RU cooperation as enabled by inter-RU fronthaul links in terms of achievable uplink sum-rate performance. We consider a C-RAN operating in a linear Wyner-type topology with partial channel connectivity and inter-RU finite-capacity fronthaul links.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
